Hollow grate-bab fob steam-boilers



A B. L. GRIFFITH, HOLLOW GRATBBAR FOR STEAM BOILERS.

vNn. 25,258.,l Patented Aug-30, 1859.

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BENJAMIN L. GRIFFITH, OF READING, PENNSYLVANIA.

HOLLOW GBATE-BAR FOB. STEAM-BOILERS.

Specification of Letters Patent No. 25,258, dated August 30, 1859.

To all whom it may concern:

Be it known that I, BENJN. L. GRIFFITH, of Reading, Berks county, Stateof Pennsylvania, have invented a new and useful Improvement in HollowGrate-Bars for Steam- Boilers; and I do hereby declare the following tobe a full, clear, and exact description of the same, reference being hadto the accompanying drawing and to the letters of reference markedthereon.

y invention relates to an improvement in the construction of hollowgrate bars for steam boilers, and my improvement consists in two or moret-ubes connected at each end to the hollow boxes which are attached tothe irebox of the boiler by means of hollow screw plugs as describedhereafter, so that the water in the boiler' can have a free circulationthrough thebars, and so that the latter can be readily removed andreplaced in sections.

In order to enable others to make and use my invention I will nowproceed to describe its construction and operation.

On reference to the accompanying drawing which forms a part of thisspecification, Figure l, is the sectional plan of the fire-box of alocomotive boiler with my improved hollow grate bars. Fig. 2, asectional elevation of part of the fire box. Fig. 3, a transversesection of the same. Fig. 4, a detached view illustrating a modifiedplan of securing the grate bars to the lire box.

Similar letters refer to similar parte throughout the several views.

A, is the exterior, and B, the interior plate of a locomotive fire box,the usual water space intervening between the plates and the latter,being connected together by the ordinary stay bolts.

The grate bars consist of tubes o o, three four or more, of which, areconnected at each end to and communicate with a hollow metal box D.Three or more sets of these bars, according to the size of the lire box,arc attached to the latter in the following manner. Each of the boxes D,have two openings on the outside and near each end, and each opening iscounter-sunkso as to receive the bevel ed end of a hollow taperingscrewplug G. The latter is screwed into the firebox through both plates,and has any convenient number of openings at a point between the innerand outer casing of the fire box, so that the water in the interveningspace can pass through the hollow plugs into the boxes D, and thenceinto the pipes C, through which a circulation of water is constantlymaintained.

Vhen one of the tubes becomes worn, burnt or otherwise damaged, thewhole set of tubes to which the damaged tube may be connected is removedby partially unscrewing the plugs G, when the whole of the tubes withtheir boxes will drop to the ground, and a new set of tubes can bereadily introduced. The damaged set may then be repaired at pleasureready to take the place of another damaged set when necessary.

vInstead of connecting each set of hollow grate bars by screw plugs atboth ends, they may be connected at one end by a simple tube o., Fig.4l, which is screwed into the inner casing of the lire box, and which isbeveled at the outer end so as to lit into the countersunk opening ofthe box D.

I am aware that hollow grate bars communicating with the water spaceshave been heretofore used, also that hollow screw plugs have beenemployed for connecting detachable linings to the lire boxes oflocomotives. I therefore do not claim the separate use of such devices,but

I claim as my invention and desire to secure by Letters Patent- Two ormore, tubes C, att-ached to hollow boxes D, connected to the irebox, bymea-ns of hollow perforated screw-plugs G, and arranged in sets tocomplete t-he grate as and for the purpose herein set forth.

In testimony whereof, I have signed my name to this specification in thepresence of two subscribing witnesses.

B. L. GRIFFITH.

fitnesses HENRY HowsoN, JNO. B. KENNEY.

